Improve compatibility with VC++, patch contributed by Morten Ofstad!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17126 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/Target/X86/X86CodeEmitter.cpp b/lib/Target/X86/X86CodeEmitter.cpp
index 5bc04424ba..eef01adfb0 100644
--- a/lib/Target/X86/X86CodeEmitter.cpp
+++ b/lib/Target/X86/X86CodeEmitter.cpp
@@ -102,21 +102,34 @@ unsigned JITResolver::getLazyResolver(Function *F) {
   return Stub;
 }
 
+#ifdef _MSC_VER
+#pragma optimize("y", off)
+#endif
+
 void JITResolver::CompilationCallback() {
+#ifdef _MSC_VER
+  unsigned *StackPtr, RetAddr;
+  __asm mov StackPtr, ebp;
+  __asm mov eax, DWORD PTR [ebp + 4];
+  __asm mov RetAddr, eax;
+#else
   unsigned *StackPtr = (unsigned*)__builtin_frame_address(0);
   unsigned RetAddr = (unsigned)(intptr_t)__builtin_return_address(0);
+#endif
   assert(StackPtr[1] == RetAddr &&
          "Could not find return address on the stack!");
 
   // It's a stub if there is an interrupt marker after the call...
   bool isStub = ((unsigned char*)(intptr_t)RetAddr)[0] == 0xCD;
 
+#ifndef _MSC_VER
   // FIXME FIXME FIXME FIXME: __builtin_frame_address doesn't work if frame
   // pointer elimination has been performed.  Having a variable sized alloca
   // disables frame pointer elimination currently, even if it's dead.  This is a
   // gross hack.
   alloca(10+isStub);
   // FIXME FIXME FIXME FIXME
+#endif
 
   // The call instruction should have pushed the return value onto the stack...
   RetAddr -= 4;  // Backtrack to the reference itself...
@@ -150,6 +163,10 @@ void JITResolver::CompilationCallback() {
   StackPtr[1] -= 5;
 }
 
+#ifdef _MSC_VER
+#pragma optimize( "", on )
+#endif
+
 /// emitStubForFunction - This method is used by the JIT when it needs to emit
 /// the address of a function for a function whose code has not yet been
 /// generated.  In order to do this, it generates a stub which jumps to the lazy